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XPS 研究表明,在空气中久置后的 Y_2O_3,BaO 和 CuO 以及 YBa_2Cu_3O_(～7),超导体的表面都生成有碳酸盐.超导体中的元素价态为:钇+3价,钡+2价,铜主要+2价.原料 CuO 在真空中在400℃加热后大部分被还原成 Cu_2O;制备不久的超导体在同样条件下其 Cu~(2+)离子较难还原,然而在空气中久置后的超导体中的 Cu~(2+)又较易还原.这些现象既反映了原料氧化物经烧结后由于生成了 YBa_2Cu_3O_(~7)相而增加了稳定性,又说明这种超导材料仍具有亚稳性质.
XPS studies show that carbonates are formed on the surface of superconductors Y_2O_3, BaO and CuO and YBa_2Cu_3O_ (~ 7) after a long time in the air.The valence states of elements in superconductors are: yttrium +3 valence, barium + valence , The main copper +2 price of raw materials CuO in a vacuum heated at 400 ℃ most of the reduced to Cu_2O; prepared superconductors in the same conditions Cu ~ (2+) ions more difficult to restore, however, in the air for a long time The post-superconducting Cu 2+ is easier to be reduced, which reflects the stability of the YBa 2 Cu 3 O 7 phase after the sintering of the starting oxide, With metastable properties.